connecting multiple fans to 1 fanmate?

tomy · Post by **tomy** » Thu Oct 11, 2007 9:56 am

its hard to search thru these many posts,
is it ok to connect more than one fan to the zalman fanmate? (i have the first version)

i just hooked up 2 zalman 92mm, and the fanmate is at minimum
seems to be ok (no fire yet), but i'm wondering if adding another would be too much?

Jan Kivar · Post by **Jan Kivar** » Sat Oct 13, 2007 9:14 am

It mainly depends on the wattage required by the fans. Fan Mates are spec'd to 6 watts, or 0,5 A (Ohms law, assuming 12 V supply). If you have a multimeter, you can measure the current while operating a single fan to see whether it would be safe to use two or more fans.

From the Fan Mate's view, the worst case scenario is when the output voltage is half of the supply voltage (6 V in case of 12 V supply). At this output voltage the power dissipation in the Fan Mate is the greatest; 0,25 times the fan's nominal power usage with 12 V supply*. Running the Fan Mate at it's minimum setting (5 V) is slightly easier to the Fan Mate.

If you want to do the math, don't trust blindly to the fan manufacturer's values for current/power. Most fans use less power than they are rated for, some have more leeway in the specs than others. The basic rule is: "The faster the fan, the more it consumes power".

For the record, I'm currently using three fans (two 120 mm Nexus and one 80 mm Nexus) with a single Fan Mate 2. I'm operating close to the worst case voltage. These are all low speed fans, so the situation might be different with those Zalman fans, which aren't really low speed fans.

Cheers,

Jan

*Maxim/Dallas - Fan Speed Control is Cool!

SilentShoe · Post by **SilentShoe** » Sat Oct 13, 2007 7:34 pm

I never knew multiple fans could be connected to the fanmate seeing as it only has 1 3pin in.
How do you guys get multiple 3 pin ins to connect to the fanmate/2?
kinda noobie here

tomy · Post by **tomy** » Sat Oct 13, 2007 7:43 pm

i got a paperclip and cut 3 parts about 3/4 inch long,
plugged 1 fan in fanmate, the 3 paperclip parts in the top holes of the connected connector, then plug the 2nd fan into the paperclip,
fits like a glove

SilentShoe · Post by **SilentShoe** » Sat Oct 13, 2007 7:55 pm

the paperclip acting as a conductor?!!

SMARTS!

I might consider this when i run out of fanmates. meaning get more fans

I wonder how Jan Kivar does it

Jan Kivar · Post by **Jan Kivar** » Sat Oct 13, 2007 10:32 pm

I really wouldn't recommend that paper clip thing to anyone. You'll easily short-circuit the Fan Mate, which will then burn out. Luckily for tomy's case, the Fan Mate should act as a fuse in such a situation, most likely preventing any other damage.

Should the paper clips be attached directly to a Molex connector from the PSU, the aftermath might be quite different. A short in a Molex connector could cause anything from abrupt power-off to burnt fingers and molten cables. If the OCP (over current protection) is sub-par in the PSU (cheap no-name PSUs), the PSU could even break down completely or catch fire.

To answer SilentShoe's question, there are two ways.

Use a fan that has both a 3-pin connector and a Molex pass-through, as the Nexus fans. Connect the Fan Mate to the 3-pin connector and chain the rest of the fans with the Molex connectors.
Use 3-pin cable splitters as depicted here. This is useful if the fans have only a 3-pin connector, but it gets rather expensive, as the stores usually have only 1-to-2 splitters, so three fans would require two of those splitters. The 3-pin connectors and receptacles are are available from many electronics shops, so if one is handy with a soldering iron, a 1-to-3 splitter is quite easy to make. The RPM cables can be omitted from such a splitter.

Cheers,

Jan

SilentShoe · Post by **SilentShoe** » Sun Oct 14, 2007 9:43 am

Thank you very much Jan.
I never knew that power could be transfered through the 3 pin to the 3 pin molex.

I plan on getting 2x 92mm nexus, this will save me from using an extra fanmate!

thanks again for clarifying.

Aris · Post by **Aris** » Tue Oct 16, 2007 4:06 pm

I have had up to 3x fans on a single fanmate without issue. 2x 120mm and a 92mm, all nexus. I just connect it to a molex connector'd fan, and they all come with a splitter, so i just connect all the fans to each other, and then one of the fans to the fanmate. Pretty simple really.

Now granted i dont get individual fan control, but for me i dont care. I just set them all as slow as i can where they will still reliably start up.